To facilitate the transfer of digital information between computer systems, computers are often connected together in networks. For example, the personal computers at most offices are coupled together using a local area network (LAN) such as Ethernet. Coupling together the personal computers in an office enables the co-workers to quickly easily transmit electronic mail messages and transfer data files.
To further make computer resources easily accessible, many people now use portable computer systems. Portable computer systems enable a user to access computer resources anywhere, anytime. Portable computer systems range in power and complexity from small simple palmtop organizers to portable workstations.
However, a portable computer system is often not easy to incorporate into a computer network due to its portable nature. Currently, network communication with portable computer systems is based on one of two paradigms: (1) A direct connection from the portable computer system to a computer communications infrastructure thereby allowing full network access; or (2) The composition and queuing of messages, pending a direct connection to the communication infrastructure.
Only when a portable computer system has a direct connection to a computer communications infrastructure can the portable computer system transmit electronic message. The direct connection between the portable computer system and the computer communications infrastructure can consists of a direct wired connection or a wireless connection.
Examples of direct wired connections between a portable computer system and a computer communications infrastructure include Ethernet LAN connections, a token ring LAN connections, or a telephone line and a modem. Direct wired connections usually are the most cost-effective computer communication solutions, however direct wired connections cannot be used in portable computer systems such as palmtop computers that are used during transit.
Alternatively, the direct connection between the portable computer system and the computer communications infrastructure may comprise a wireless connection such as a wireless cellular modem or digital packet radio. An important aspect of a wireless communication system is the amount of "coverage" that is supported by the wireless communication system. The coverage is defined as an area from which a user can send and receive messages. The coverage area can be quantified by its size and location. If a user moves out of the coverage area, the user will be unable to send or receive messages.
To increase the coverage area of a wireless system, wireless communication vendor can install more transmitter/receiver stations. Alternatively, the wireless communication vendor can amplify the signals transmitted by the transmitter/receiver stations. Either solution requires a major investment by the wireless communication vendor.
If a user of a wireless communications service moves out of the coverage area, then the portable computer system can not send or receive any messages. To handle electronic messaging while a portable computer system is not connected to a computer communications infrastructure most portable computer systems allow for the composition and queuing of messages, pending a direct connection to the communication infrastructure. When the portable computer system eventually establishes direct connection with the computer communications infrastructure, all the queued messages are then transmitted. Thus, any queued message must wait an indeterminate amount of time until a direct connection is established so that messages can be transmitted.
To reduce the lag time for pending messages, it would be desirable to increase the coverage area of a wireless communication system. However, increasing the coverage area of a wireless communication system usually requires the added cost of installing additional transmitter/receiver stations. Thus it would be desirable to find an inexpensive method of increasing the coverage area of a wireless communication system.